The invention relates generally to a method and a composition for the treatment of wastewater collection systems. More specifically, the invention relates to a method and a composition for removing and preventing buildup of blackwater deposit in a blackwater collection and/or treatment system typically used in large transportation systems.
Waste collection and/or treatment systems are directed primarily to collecting and treating human waste. In many circumstances, such waste systems involve the use of high volumes of water to dilute the waste and move the waste through the system to a holding or treatment station. However, in some circumstances, the use of high volumes of water is impractical, or impossible. For example, waste collection/treatment systems on vehicles, such as ships, trains, aircraft, or other such vehicles pose difficulties. The water and waste are often stored within the vehicles until proper disposal can take place, thereby creating space and weight concerns. The use of high volumes of water are clearly impractical. In other situations, waste collection/treatment systems have to operate in areas having little or no access to water.
In such low water volume situations, the waste within the waste collection/treatment system is highly concentrated. Such highly concentrated, high solids content, low water volume waste is often referred to as low water (solvent) volume blackwater waste. One problem that arises in a low solvent volume system is that, due to the concentrated nature of the waste, a hardened deposit, known as blackwater deposit, can collect within the pipes and holding tanks of the system. Persistent problems arise with blackwater deposits reducing the capacity or clogging the system, especially in an entry port, narrower pipe sections and corner pipe sections.
In particular, the cruise ship industry has reported persistent problems with blackwater deposits in low water volume blackwater collection/treatment systems on cruise ships. The industry would often refer to the deposits as uric acid crystals, or xe2x80x9curine crystalsxe2x80x9d, and would attempt to remove the deposits from the systems with hydrochloric acid (HCl), a strong acid. HCl would be dispersed into vacuum toilet Units of the shipboard systems, followed by repeated flushing. However, the use of HCl alone has had limited effectiveness on removing the blackwater deposits, and often resulted in serious corrosion of the mild steel which is often used in collection/treatment system vacuum lines.
Another problem involves the treatment of low water volume blackwater collection/treatment systems on vessels such as ships; trains or aircraft is that such vessels often have space constraints, thereby making it difficult to manually apply treatment compositions to the collection/treatment systems.
Therefore, there is a continuing need for a better composition and method for the treatment of blackwater deposit in blackwater collection/treatment systems.
The inventors have developed a composition and method particularly designed to treat problematic blackwater deposit. In at least one embodiment, the invention relates to a composition for use in removing and preventing buildup of blackwater deposits in blackwater collection/treatment systems. The composition includes in the range of about 2 to about 15 wt. % of acidic solubilizing agent; in the range of about 0.2 to about 8 wt. % of wetting agent; and in the range of about 0 to about 1 wt. % corrosion inhibitor; and a solvent/carrier medium.
In another embodiment, a concentrated composition is provided that can be diluted with additional solvent/carrier medium before or during use to provide for a use composition for use in removing and preventing buildup of blackwater deposits in blackwater collection/treatment systems. Generally, the concentrated composition, either during or prior to use, is diluted into a use composition having the concentration of components given above. The concentrated composition, which is used with a dilution scheme, includes in the range of about 10 to about 75 wt. % of acidic solubilizing agent; in the range of about 1 to about 40 wt. % of wetting agent; and in the range of about 0 to about 5 wt. % corrosion inhibitor; and the balance being a solvent/carrier medium.
In another aspect, the invention involves a method for removing and preventing buildup of blackwater deposit in a blackwater collection system. In at least one example, the method includes: contacting at least a portion of the black water collection system with the blackwater deposit treatment composition above; and removing at least a portion of the treatment composition from the portion of the blackwater collection system.
The features of novelty and various other advantages, which characterize the invention, are pointed out with particularly in the claims annexed hereto and forming a part hereof. For a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the following descriptive matter and drawing, in which there is described and depicted a preferred embodiment of the invention. However, before embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of components set forth in the following description and drawing. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used in the description is for the purpose of description and should not be regarded as limiting.